According to the information available to us, since 1958, the year corresponding to the first permanent implantation of a pacemaker (see: Historical aspects of the cardiac pacing in "Cardiac Pacing", Escher, D. second edition--page 631--Ed. Samet-El-Sherif, Grune and Stratton, N.Y., 1980, U.S.A.), and up to now, all pacemaker implantations require an electrode or catheter to stimulate the heart. Said electrode may be monopolar or bipolar, as is well known by those skilled in the art.
Such electrode or catheter, upon being monopolar, consists of a helical and very resilient "electric wire", one of the ends of which, namely the one opposite to the aforementioned tip, is to be connected to said plug-receptacle, while the aforementioned tip is to be connected to the heart muscle itself. In these known electrodes, the electric wire is housed in an electrically insulating sheath, with the exception of the aforementioned connecting end and tip.
According to statistics, nowadays the stimulation failures range between 0.5 and 9% produced by the pacemaker's circuitry. On the other hand, failures originated by the electrode itself are much higher, since they range between 2 and 18% (see "Marcapasos Cardiacos"--Cardiac Pacemakers--Trabucco, H. O. and adts. Ed. "El Ateneo"--page 146, 1989, Buenos Aires, Argentina).
It may be added, that the length of such an electrode ranges usually between 30 and 70 cm. The failures in those known electrodes or catheters are usually due to:
a) Failures in relationship to the fixation of the connecting end of the electrode in the plug-receptacle of the pacemaker's housing.
b) Failures, due to breaking, wearing, tearing or ageing of the insulating sheath, bearing in mind that the electrode is subject to mechanical and chemical stresses.
c) Failures, due to breaking of the electrode.
d) Failures, due to electrode tip dislocations from the selected implantation, which often generates cardiac arrest or potentially dangerous cardiac arrythmias.
e) Failures, due to perforating the heart muscle during implantation or during the immediate follow-up.
f) Failures, due to increase of the electric resistance or high threshold in the interface electrode tip/heart muscle developing an "exit block", which high threshold can be reduced using the FIG. 4 embodiment of the present invention, as will be later explained.
All these failures or complications lead to an irregular functioning of the stimulating system, which can be temporary or even permanent. In both cases it threatens the patient's life. Since the proposed pacemaker does not require a catheter, failures a) to e) become non-existant.